• A horizontal and a vertical number line are used to divide a plane into four regions, called quadrants.
  • A plane set up according to this system is known as a coordinate plane .
  • The horizontal line is called the X-axis, and numbers on this axis are called X-coordinates.
  • The vertical line is called the Y-axis, and numbers on this axis are called Y-coordinates.
  • The intersection of the X-axis and the Y-axis is a point called the origin
  • The order in which you name the coordinates is important. This means that a point identified by (10,5) is different from a point identified by (5,10). For this reason, the coordinates of a point on a coordinate plane are called an ordered pair.
  • The origin has coordinates: (X,Y)
The example graph shows the following points:
  • A= (4,4)
  • B= (-1,3)
  • C= (6,-2)
  • D= (2,6)
  • E= (10,3)
  • F= (7,4)
graph_1.png